Above, ecologist Ray Carruthers examines saltcedar
along Cache Creek in Yolo County, Calif. Below, the leaf beetle Diorhabda
elongata was the first approved biological control agent for saltcedar in
the United States. Click the images for more information about
them.

Beneficial Beetles Battle Pesky Saltcedar

Tiny beetles that munch on saltcedar
leaves, shoots and twig bark are helping stop the spread of this rugged,
aggressive weed. Also known as tamarisk, saltcedar was brought into the United
States in the 1800s to help control erosion. By the mid-1900s, however,
saltcedar had become an out-of-control pest, crowding native plants, such as
cottonwoods and willows, along streambanks and river channels throughout the
American West.

Agricultural Research Service (ARS)
entomologist
C. Jack
DeLoach, ARS ecologist
Raymond
I. Carruthers, and their co-investigators have found that a leafbeetle that
they've investigated and helped import, Diorhabda elongata, has now
defoliated hundreds of acres of saltcedar-infested test sites in Colorado,
Nevada, Utah and Wyoming. Yet the beetle poses no hazard to people, pets or
crops.

The outdoor tests, begun in 2001, represent the first time any natural
organism had been lined up to tackle tamarisk. Collected from saltcedar in the
Mediterranean region as well as in China, Kazakhstan, and other parts of
Asia--all lands where the troublesome tree is native--the beetles devour
saltcedar's scale-like leaves. That happens when the insect is in its
caterpillar-like larval stage or has matured into a quarter-inch-long adult
beetle.